How To: Get Rid of Whiteflies
These tiny winged insects can devastate vegetable gardens and ornamental plants, but home gardeners can stop stop them without resorting to pesticides.
The first sign of a budding whitefly infestation may be a host of tiny white flying insects rising from a plant when its leaves are disturbed. If left untreated, whiteflies (Trialeurodes vaporariorum) can quickly overtake a plant, penetrating the stems and sucking out the life-giving juices within.
Whiteflies are related to mealybugs and aphids, but not household flies, and are identified by their yellow-hued bodies and two sets of white wings. Whiteflies feed on both houseplants and outdoor plants, and they propagate rapidly during the warm summer season. Getting rid of them requires vigilance and persistence, but it’s doable. Best of all, you won’t need harsh pesticides.
A few common ingredients and some simple tools can be used for eradicating whiteflies. You probably won’t need all of these items to get rid of the insects, but using a few should keep whiteflies from setting up residence in your garden.
BEFORE YOU BEGIN
At the first indication that whiteflies are settling on plants, some growers reach for toxic chemicals to control them. Though this strategy might work, according to Planet Natural Research Center, whiteflies have developed resistance to some pesticides.
The following methods of eradicating these tiny destroyers involve natural, homemade, or organic ways to control the insects, which makes them better for the environment—and safer to use on food-producing plants.
STEP 1: Vacuum infected plants.
The first step in stopping whiteflies is to get them off the plant. Shooing them away or flicking them off won’t work. They’ll come right back. Instead, suck the insects up with a small handheld vacuum. Vacuuming will remove the flies and their larvae—just be sure to lift the leaves and vacuum the undersides as well. Vacuuming can also be helpful in controlling other types of indoor pests.
Once you’ve hoovered the little pests, don’t dump the collection bin in the trash. The whiteflies will fly out and head back to the plants again. A better idea is to dump the little buggers into a plastic bag, and seal the bag before throwing it away.
STEP 2: Remove the most damaged leaves.
Whiteflies tend to feed on one leaf and then another, sucking out all the leaf’s juices before moving on to the next one. When this happens the plant continues to send energy to the damaged leaves until they’re removed, though the damaged leaves are well past saving.
Using a sharp garden nipper or pruning shears, clip off wilted leaves as well as those that are covered in a sticky, waxy fluid. The fluid, called honeydew, is secreted by the whiteflies after ingesting the plant’s vital juices. Seal the clipped-off leaves in a plastic bag before tossing them in the trash.
STEP 3: Clean leaves and stems with spray.
A simple solution made from liquid dish soap and water will kill adult whiteflies without harming plants. Add 1 tablespoon of liquid dish soap to 1 gallon of water and mix well. Pour the solution into a plastic spray bottle and spray it on all infested plants, saturating the leaves’ upper and undersides and the stems.
The dish soap solution will kill adult whiteflies. If eggs remain on the plants, they will hatch in 3 to 4 days and reinfest them. Be sure to respray affected plants every couple of days to kill any whiteflies that have hatched in the meantime.
STEP 4: Help plants battle pests.
Keeping plants healthy by watering and fertilizing will make them strong enough to survive a whitefly infestation. A weak plant will succumb more quickly. If you find that whiteflies are a persistent problem in the garden or on your indoor plants, consider adding earthworm castings to your soil.
Earthworm castings repel whiteflies and as castings decompose, they also act as an organic fertilizer to boost the plant’s health. Castings can also be sprinkled on leaves to keep whiteflies away.
STEP 5: Get rid of the newcomers.
Keeping a close eye on your garden will allow you to get rid of whiteflies before they can damage or kill your plants. Neem oil, an extract from the seeds of neem trees, can get rid of whiteflies without harming plants. This natural pesticide repels whiteflies and can be applied to plants at the first sight of a white-winged pest.
Neem oil comes in various forms, including concentrated liquid that can be diluted in water and sprayed on plants. It is also available as a granular that can be mixed into the soil, or a dust that can be applied to leaves and stems. Follow the package directions for use.
STEP 6: Think about long-term protection.
It’s not always easy to spot a whitefly infestation and stop the bugs before they substantially damage plants, which is why taking steps to repel the insects is just as important, if not more so, as treating existing infestations. Companion planting can help.
Plants that naturally repel whiteflies include catnip, bee balm, basil, chives, dill, and marigolds. By planting them in the garden, whiteflies and other pests such as spider mites are less likely to move in.
Without quick action, whiteflies can severely damage or destroy many types of plants, including squash, cucumber, tomatoes, and other warm-season vegetables. They can also damage roses and other ornamentals. Citrus trees are not immune to whiteflies, either. The good news is that these methods for stopping a whitefly infestation and preventing future ones will not harm plants or the environment.